Changing a PDF’s page size rescales the existing page content to fit a new set of dimensions. The tool reads each page, calculates a scale factor from the original dimensions to the target size, and writes a new PDF with the content scaled and centred on the target page. The whole process runs in your browser with no file upload.
Free Resize PDF — runs in your browser
A4, Letter, Legal, A3, A5. No uploads. No account.
Change PDF page sizeA4 vs US Letter: what is the difference?
A4 and US Letter are close in size but not identical, and this small difference causes a surprising number of printing problems when documents cross borders:
| Size | Dimensions (mm) | Dimensions (inches) | Used in |
|---|---|---|---|
| A4 | 210 × 297 | 8.27 × 11.69 | Europe, Asia, Australia, most of world |
| US Letter | 216 × 279 | 8.5 × 11.0 | USA, Canada, some Latin America |
Letter is 6mm wider and 18mm shorter than A4. An A4 PDF printed on a US Letter printer will have a 18mm gap at the bottom. A Letter PDF printed on A4 paper may clip up to 6mm off the sides if the printer does not auto-scale.
If you regularly exchange documents with organisations in different countries, converting to the recipient’s paper standard before sending avoids these issues.
How to change PDF page size step by step
Open the Resize PDF tool
Upload your PDF
Drag your file onto the drop zone or click to browse. Nothing leaves your device.
Select the target page size
Choose from A4, US Letter, US Legal, A3, or A5. The tool applies the same target size to every page.
Click Resize
The tool scales and repositions each page’s content to fit the new dimensions.
Download
Click Download to save the resized PDF.
Standard page sizes reference
| Size | mm | inches | Common uses |
|---|---|---|---|
| A3 | 297 × 420 | 11.69 × 16.54 | Large diagrams, posters, double A4 spreads |
| A4 | 210 × 297 | 8.27 × 11.69 | Standard document format worldwide |
| A5 | 148 × 210 | 5.83 × 8.27 | Booklets, flyers, half-A4 |
| US Letter | 216 × 279 | 8.5 × 11.0 | US/Canada standard |
| US Legal | 216 × 356 | 8.5 × 14.0 | Legal documents, contracts, US courts |
When to resize a PDF
The most common scenarios where page size conversion is needed:
- Cross-border printing — a document designed in Europe (A4) being printed in the US (Letter), or vice versa
- Binding requirements — a thesis or report required to be on a specific paper size
- Print shop submission — commercial printers often require PDF files to match the exact paper size they are printing on
- Booklet creation — resizing A4 to A5 to create a folded booklet from a standard document
- Large-format printing — scaling up a document to A3 for poster or display printing
- Inconsistent page sizes — a merged document has mixed A4 and Letter pages; resize all to a single standard
Does resizing affect quality?
Resizing scales the page content. The effect on quality depends on what is in the document:
- Vector content (text, shapes, diagrams) — scales perfectly at any size. No quality loss at all.
- Raster images (photos, scanned pages) — scaling down is fine; the image pixel count stays the same but is displayed smaller. Scaling up may soften raster images because you are stretching pixels.
For A4 ↔ Letter conversion, the scale factor is about 3% in each direction — barely perceptible even on raster images. For A4 → A3, the scale is 141% (the √2 ratio of the ISO paper series), which can soften raster images noticeably. For print-quality work at A3, ensure your source images are at 300 DPI before resizing.
Frequently asked questions
What is the difference between A4 and US Letter?
Will resizing a PDF change text or image quality?
Can I resize only specific pages?
What page sizes are supported?
My PDF prints with white borders or gets clipped. How do I fix it?
Is it safe to resize a confidential PDF online?
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